2003 XJ900S - scary handling problem..

[ewano]

I've posted this over at the Diversion forum at bikers oracle, and again here. Hope I can get some feedback from people who might have experienced this before.

I've found a rather disturbing problem with my D9 at high speed.

As my speed built, I found the front of the bike starting to feel like a jackhammer. Slowing up made it go away and as I took the speed back up it happened again. It wasn't a speed wobble, it was a more vertical plane movement just like holding a pneumatic drill.

My first thought was that the front wheel could be out of balance, and I know that the previous owner used some type of tyre sealant goop in the wheels so balancing is not an option. I was wondering if anyone else has had anything similar and recognises the problem.

It's not too much or a problem as it's stable up to a reasonable cruising speed. So I can just not get up to that speed again and I'll be fine, but would be nice to know that it's not going to get hairy on me if I'm passing at speed on the motorway.

However I'm also thinking of changing the tyres on the bike (I think it's still on it's original set as it's only done 8500 miles) and wondering what peoples recomendations for a D9 would be.

Ewano.

[El Fuego]

Tyres would be Avon Storm ST's or Bridgestone BT021's I reckon. (I recently got a Storm ST rear as I still have an Azzaro front).

Does the jackhammer effect happen when you're cranked over or upright? (Or both).

Are your fork preloads set the same?

Have you lost any oil out of one of your forks?

[Fiasco]

Hi Ewano

I am pretty sure I had the same problem with my first 900 after putting Puntureseal in. The jumping front wheel happened at between 105-110mph (off road of course) and stopped as soon as I dropped the pace.

8500 miles is pretty good going for original tyres, are they Dunlop 505s? I think that was the original ones.

Maybe time for a change of tyres as you say, the front can have loads of tread left but still be out of shape. I would recommend BT020s or Conti Road Attacks personally.

HTH

Dave ;D

[ewano]

Hi Dave,

Yeah, testing off the road showed that it cut in about 105 mph. Havn't looked at the tyres properly, as I've only had the bike a few weeks and have been had the chance to get out on it about four times so far, what with all this bloody rain!

Still the sun is out tonight and I might head out for a little spin..

Ewano

[HRHpenfold]

happened to mine, when i overfilled with puncturseal,

i have dunlops on my new one, but will be changing them soon ;D

[ewano]

Anyone with puncturseal in their tyres managed to get a bike that's stable into the high speed range?

I like the idea of having an anti puncture goop in there, but not if it means I have to endure handling problems when I want to go quick. Is it a case of badly installed puncturseal type goop, or is it more a case of "this is what happens when you use goop"?

Ewano

[beeblemaster]

ewano said:

Anyone with puncturseal in their tyres managed to get a bike that's stable into the high speed range?

Nowt wrong with mine

[General Gman]

When you install puncture sealant, you do need to ride the thing for 20-30 miles at normal speeds to distribute evenly around the circumference of the tyre.I would be looking at a new tyre at 8500 miles, though - once the profile of the front is eroded, you can get all sorts of handling problems.

[Ghoti]

I had something similar on the Fazer. When fully loaded with top box and panniers at about 90. With an empty top box I get it at about 110 and with nothing it is good for 140 (when I bottle out).

Have you got a top box on?

This was abroad so abviously all speeds are kmh, or on a German Autobhan!

Mind you, front wheel balance seems likely to me (and indeed, that is what I thought at first). Taking weights off or adding them (in a very non scientific way) made not difference to the problem.

Softening the front suspension helped a little though. Have you got a D9 that you can change the front suspension?

[ewano]

Ghoti,

No boxes. Just an unladen wingrack. This only kicked in at a certain speed. No matter if I built the speed slow or fast, so I suspect it's not a rack tension problem either.

I'll have a good look at my tyres when the weather permits, but TBH it sounds to me like I'm just going to have to either ride slow(er) till the tyres need a change, or just change them now and get it sorted.

I only got the bike three weeks or so ago, and so I've not really had a close look at things like the make of rubber on there etc. I suspect it's on it's first set of rubbers due to milage, but I might well be wrong.

Ewano

[ewano]

Well, the sun is here at last!

Took the bike out for a spin at the weekend and had a great time riding in the dales of Co. Durham. Hit a bit of rain up at alston, but nothing too much. Had a look at the tyres - Dunlops. Looks like I could do with changing them, so I'm going to investigate where's a good place to do it in Newcastle. I'll also have a look at the recomendations board and see what people are saying about tyres.

I'm now wondering if I should bother with Puntureseal for the tyre, or just carry a foam canister under the saddle.

I'm extremely loath to encounter this handling problem again.

[El Fuego]

I got my new rear tyre (Avon Storm ST ... 150/70 ZR 17) from National Tyres. (Don't know if all outlets do bike tyres). They have to order it in, so you go and order/pay then it comes within a day or two.

I don't have puncture seal fitted.

[ewano]

How odd.

You are in Strathaven, but your band seems to be based in my home town laddo. What's the score with that then?

You an exciled Geordie or a wannabe interloper?

Ewano - still not decided on tyres, although it might have come down to a choice between some BT21's or some Conti Road attacks.

[ewano]

Well,

Today I priced up some tires

Conti Road Attacks against BT020's and the £19 difference made me plump for the BT020's.

Ride in service at M&S West Road in Newcastle both fitted, and balanced while I had a poke about in some shops and a bacon, Egg and Beans stottie and a cuppa cost me £206.

Pricey, but then again I could have saved some money and bought the tires from Ebay (4 days wait), removed the wheels(when it's not raining) and taken them down to the shop next weekend , collected them later that day and assuming it's not raining fit the wheels again which would have saved me about £50 - instead I paid the man and went out for a ride in the sun.

Didn't get a chance to test the handling, due to having to scrub the tires in and let them settle properly - but the bike seems much better planted in the corners than with the original Dunlops that were on there..

Ewano - with a big smile on his face..

[HRHpenfold]

the problems happen, when you overfill with punctureseal, very tempting just to add a bit extra but its what unbalances it, have just got some to fit to my Fazer 600, because i picked up a puncture on the France run and had to repair it, as the tyre is fairly new, i will put the puncture seal in as an extra safety measure, why dont you show your bike off and join in the Lakes run?

[El Fuego]

ewano said:

How odd.

You are in Strathaven, but your band seems to be based in my home town laddo. What's the score with that then?

You an exciled Geordie or a wannabe interloper?

Yes - exiled Geordie. I last lived in Birtley (10 years ago). My older bro still lives there, and younger bro lives in Bedlington.

However the band ain't mine - my niece is the lead singer so I'm just helping to promote them via viral marketing.

[ewano]

Just downloaded some tracks from the website, pretty god stuff. I might try to get along to a gig sometime.

Ewano

[El Fuego]

The Myspace website tends to be more up-to-date than the one in my sig. Check the gigs guide there.

PS - I know the music is great, but religious? ;D

[ewano]

El Fuego:

Don't start, you're the one up in religious nutter land matey... All I'll say is it's a good job you don't have a green bike.

HRH

I've actually just decided to go back out on the road for a bit, and that weekend I'll probably be busy getting the bike ready, and setting off for Poland - via Calais or maybe via Amsterdam.

After that, not sure, might head down to Greece for a look about. Probably via Czech rep, Romania, Bulgaria and then Greece. Maybe come back through Italy and then France..

Dunno yet, might just stuck about in Germany.

Anyway, it's not likely I'll head over to the lakes.